1908] Grinnell—Biota of the San Bernardino Mountains. 109 
were noted August 11 to 13 evidently in migration ; also at Cactus 
Flat, August 14 to 16, and at the north base of Sugarloaf, August 
21. Fifteen specimens of this vireo were taken. 
Lanivireo solitarius cassinii (Xantus). Cassin Vireo. 
This vireo ranged well up through the Transition zone chiefly 
along canons. It was nesting commonly along Mountain Home 
ereek and along the upper Santa Ana from Seven Oaks to Fish 
ereek, then up this latter stream to nearly 7000 feet altitude. A 
ereat many nests were found in this region. The nests were of 
the usual pensile type, common to vireos generally, and averaged 
in height from the ground (estimated) eight feet, extreme heights 
being two and one-half feet and fifteen feet. Perhaps golden 
oaks at lower levels and cottonwoods at higher altitudes were 
the trees most often selected; but nests were also found in the 
incense cedar, silver fir, Jeffrey pine, black oak, and alder. 
A single nest and set may be described as typical of all. The 
nest was twelve feet from the ground in the lower outer foliage 
of an incense cedar growing among firs at the mouth of Fish 
creek. The nest was suspended by the rim, on opposite sides, 
from a V-forking twig. Externally the nest consists of gray 
inner willow bark, weathered grasses, bits of plant down, spiders’ 
ege cocoons, and plenty of web, so that the parts of the mass 
adhere together tenaciously. The material constituting the inner 
lining is wholly fine, brown, round plant stems. The dimensions 
of the nest-cavity are: depth 1.25 inches, diameter 2.02. The 
egos measure in inches .77X.56, .78.57, .79.56, and .77.56. 
They were plain white, sparsely marked with bold smallish spots 
of burnt umber and drab. These markings are mostly congested 
into a belt about the larger end. 
Small young were found near Skinner’s on Mountain Home 
creek, June 9, 1906; and a set of four fresh eggs at the mouth of 
Fish creek, June 29, 1906. These indicate the range of the 
breeding season. Four is the usual full set of eggs laid, ocea- 
sionally only three. 
We found a few Cassin vireos at Bluff lake in July, 1905, 
and again the last three days of August and up to September 3. 
Several were also seen at the north base of Sugarloaf, August 19 
